Tanoshii Muumin Ikka  

Delightful Moomin Family, Fun Family Moomin, I Mumindalen, Les Moomins, Los Moomin, Los Mumins, Moomin (1990)

Spring has arrived in Moomin Valley, signaling the start of a new adventure for Moomintroll and his friends. Snufkin returns from his winter migration, causing the valley's inhabitants to emerge from hibernation. While exploring, Moomintroll discovers a mysterious hat that he cannot throw away due to its high quality. He hopes to find its owner someday. During playtime with his friends, Moomin tries to hide in the hat but is discovered when they come looking for him. To their surprise, Moomin has transformed into an unsightly creature. Disgusted by his reflection in the mirror, he transforms back to normal and scares his loved ones. With Snufkin, Moomintroll decides to toss the hat into the river, wondering who its owner might be and whether they will return for it.

Based on the classic Swedish-Finnish childrens series by Tove Jansson, Tanoshii Muumin Ikka starts off from the events of the third novel, "Finn Family Moomintrol."